Air handling systems used in HVAC applications to control air flow. Such handing systems typically include a network of duct components, such as duct elements and duct couplings that are fastened together to provide appropriate air flow to the desired locations. In order to provide an appropriate network, flanged rings are often used to facilitate connection between rectangular, circular and oval shaped duct elements and/or duct couplings. In particular, it is known to provide flanged circular or oval-shaped rings to connect corresponding circular and oval-shaped duct components. U.S. Pat. No. 5,983,496 to Hermanson discloses known circular and oval flanged rings. As set forth by Hermanson, flanged rings might include an elongated base and an elongated protrusion extended from the elongated base. In order to form such flanged rings, Hermanson discloses a method of spin forming the rings. While spin forming flanged rings might be desirable in certain situations, the process of spin forming can be time consuming and therefore might involve excessive manufacturing costs.
With an L-shaped flange profile, it is known to roll a flange to provide the desired flanged ring. For example, FIGS. 1-3 demonstrate a known process of forming a flanged ring from an L-shaped flange. The flanged ring is formed from an elongated straight flange with an elongated base 44 and an inner flange 42 forming an L-shaped flange profile. FIG. 1 illustrates a conventional device 20 for forming the L-shaped flanged ring. The device 20 includes an upper roller 22 and a lower roller 24. The rollers 22, 24 are adapted to provide a higher compressive force at an outer portion 44a of the elongated base 44 than an inner portion 44b of the elongated base. As the elongated straight flange is fed with respect to the device 20, the elongated base is compressed to increase the length of the outer portion 44a relative to the inner portion 44b, therefore forming an elongated curved extension 46.
With reference to FIG. 3, forming the flanged ring involves resting a substantially straight L-shaped flange on top of a support surface 26. A rotatable stop 30 can be adjusted along a slot to limit the extent of the curved bending of the elongated curved extension, thereby providing the curved extension with a predetermined radius of curvature. The flange is then fed with respect to the device 20 to form the elongated curved extension 46. A guide block guide block 28 is also provided to facilitate appropriate alignment of the flange with respect to the device.
The method of forming flanged rings with an L-shaped cross section described with respect to FIGS. 1-3 has the advantage of reducing production time and therefore reducing manufacturing costs. It is also desirable to provide further methods of forming flanged rings with various cross sectional profiles. For example, it is desirable to provide further methods of forming flanged rings from an elongated straight flange with an elongated base and an elongated protrusion. Forming flanged rings in such a manner might not be possible with the device depicted in FIGS. 1-3 if the protrusion has sufficient resistance to bending.